The present invention relates to a device for actuating a safety device, in particular, a roll bar, with a first sensor which actuates the safety device when a vehicle acceleration or deceleration exceeds a threshold value.
A known device of this general type for controlling a roll bar serving as a safety device for the occupants of motor vehicles is shown in U.S. Pat. No. 3,292,726. That device has a first circuit assigned to the vehicle standstill state having a first sensor which is actuated when a specific vehicle acceleration occurs and which closes the circuit, thereby energizing a release device for activating the roll bar. The second circuit, which is assigned to the vehicle driving state, contains a second sensor closed in the driving state. Connected in series with the second sensor is a third sensor which likewise closes the circuit under specific conditions acting on the safety belt, thereby again energizing the release device. Although a considerable degree of safety is guaranteed with this device, it does not take into account all the driving states causing the vehicle to overturn.
An object of the present invention is to provide a device for actuating a safety device such that it detects all the driving states which cause a vehicle to overturn and guarantees reliable activating of the release device for the roll bar.
This and other objects are attained by the present invention by providing: a first sensor which activates the safety device when the vehicle acceleration or deceleration exceeds a threshold value; a second sensor which outputs a second signal upon sensing when at least one wheel suspension is fully extended; and a third sensor for outputting a third signal upon sensing tilting vehicle around its longitudinal and transverse axes. The safety device is actuated when both the second and third signals are outputted by the second and third sensors in addition to being activated by said first sensor.
It is therefore possible, with the device according to a preferred embodiment of the present invention, to release the roll bar by essentially two procedures which depend on different release criteria. Thus, one release procedure serves for detecting relatively slow overturns not caused by a sudden impact or collision. This can occur, for example, when driving the vehicle up a slope and tipping it over from an unstable position. The other release procedure serves for detecting vehicle overturns which are caused by a collision.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.